Tinker
Im not sure where you come up with that idea that the tester is a high SS golfer. the same tester used 4 different irons . His average 7i carry was 150 yards ranging from 142 - 161. This is NOT a high swing speed golfer by any definition. Pros are pretty much all hitting 7 irons 185+ and little old me at 56 and not a big man carry my Wishon 560 or Ping i5 7i 160/165.
The study showed that the highest lofted 7i had the least carry distance and lowest trajectory and the lowest lofted ( 5 degrees lower ) had the furthest carry at 20 yards further yet even though 5* stronger in loft it also had the highest peak trajectory. That difference is attributubatle to one thing and one thing only a difference in club head design which all but displels the myth that higher loft in an iron automatically means higher trajectory.
The other important takeway was descent angle which we have found out of late can be just as , even more important than launch angle and what the pros are looking at more nowdays. The descent angles between all the 4 clubs were similar , meaning they all fell back to earth on the same angle. So he wasnt hitting kow bullets that rolled out forever with the 30 7iron nor high moon shots that plugged in their pitch with the 35. Decent angle impacts stopping distance as will the spin of the ball on that decent.
As i said above for very low swing speed golfers loft can be their friend because it keeps the ball in the air longer and assists with distance. Slower swing speed golfers should probably max out with a 7iron, particularly when using "traditional lofts and designs" but with some modern designs, as the study shows even clubs with lower lofts can produce higher and longer distances . For the tester he gained 20 yards based on head design yet with 5* different loft. This type of advancement in technology, while not for everyone , can certainly help .
as a senior with "average" swing speed its highly likely that to increase distance and trajectory you would benefit from the combination of modern design of club with a more traditional loft pattern offering the best of both . JMHO , a ball that spins more can help as well.
It would be nice to see the same study done with the same shaft in each club , but then again shaft contribution to dynamic loft in an iron isnt much.